//Given a binary tree, find its minimum depth. 
//
// The minimum depth is the number of nodes along the shortest path from the roo
//t node down to the nearest leaf node. 
//
// Note: A leaf is a node with no children. 
//
// 
// Example 1: 
//
// 
//Input: root = [3,9,20,null,null,15,7]
//Output: 2
// 
//
// Example 2: 
//
// 
//Input: root = [2,null,3,null,4,null,5,null,6]
//Output: 5
// 
//
// 
// Constraints: 
//
// 
// The number of nodes in the tree is in the range [0, 105]. 
// -1000 <= Node.val <= 1000 
// 
// Related Topics 树 深度优先搜索 广度优先搜索 
// 👍 502 👎 0


package leetcode.editor.cn;

//Java：Minimum Depth of Binary Tree
class P111MinimumDepthOfBinaryTree {
    public static void main(String[] args) {
        Solution solution = new P111MinimumDepthOfBinaryTree().new Solution();
        TreeNode root = new TreeNode(1);
        root.left = new TreeNode(2);
        root.right = new TreeNode(3);
        root.left.left = new TreeNode(4);
        root.left.right = new TreeNode(5);
        System.out.println(solution.minDepth(root));
    }
    //leetcode submit region begin(Prohibit modification and deletion)

    /**
     * Definition for a binary tree node.
     * public class TreeNode {
     * int val;
     * TreeNode left;
     * TreeNode right;
     * TreeNode() {}
     * TreeNode(int val) { this.val = val; }
     * TreeNode(int val, TreeNode left, TreeNode right) {
     * this.val = val;
     * this.left = left;
     * this.right = right;
     * }
     * }
     */
    class Solution {
        int min = Integer.MAX_VALUE;

        public int minDepth(TreeNode root) {
            if (root == null) {
                return 0;
            }
            if (root.left == null && root.right == null) {
                return 1;
            }
            if (root.left != null) {
                min = Math.min(min, minDepth(root.left) + 1);
            }
            if (root.right != null) {
                min = Math.min(min, minDepth(root.right) + 1);
            }
            return min;
        }
    }
//leetcode submit region end(Prohibit modification and deletion)

}